php - add string at offset?

Question

If I have a string like \"test\", I have characters from offset 0-3. I would like to add another string to this one at offset 6. Is there a simple PHP function that can do this?

Answer 1

Convert the string to an array, in the case where the offset is greater than the string length fill in the missing indexes with a padding character of your choice otherwise just insert the string at the corresponding array index position and implode the string array.

Please see the function below:

function addStrAtOffset($origStr,$insertStr,$offset,$paddingCha=' ')
{
    $origStrArr = str_split($origStr,1);

    if ($offset >= count($origStrArr))
    {
        for ($i = count($origStrArr) ; $i <= $offset ; $i++)
        {
            if ($i == $offset) $origStrArr[] = $insertStr;
            else $origStrArr[] = $paddingCha;
        }
    }
    else
    {
        $origStrArr[$offset] = $insertStr.$origStrArr[$offset];
    }

    return implode($origStrArr);
}

echo addStrAtOffset('test','new',6);